1. Field of the Invention
The present invention relates to a lighting apparatus, in particular, to its structure with a straight fluorescent tube.
2. Description of the Related Art
In view of energy saving required today, most of fluorescent lighting apparatus are required to increase energy efficiency thereof without deteriorating eyeshot environment. For example, JP 2004-134330 A proposes a lighting apparatus which improves energy efficiency by preventing the rise of circumferential temperature of a fluorescent tube.
However, a main body of the lighting apparatus disclosed in JP 2004-134330 A has a box shape structure which comprises a bottom plate and four side plates. This results in a structure that is low in rigidity and is easy to deform or distort.
These days, as a fluorescent tube having an excellent potential on the energy saving, a high-intensity fluorescent tube having a diameter of approximately 16 mm with its light emitting efficiency improved by 20% compared to that of a conventional fluorescent tube is being manufactured and supplied. However, the box-shaped lighting apparatus as described in JP 2004-134330 A does not have enough rigidity to support such a fluorescent tube having a small diameter.